Method for chromatographic purification of a fatty acid

Abstract

The invention related to a method for purifying a first fatty acid, preferably polyunsaturated, using an initial mixture further comprising at least one second fatty acid, optionally a third fatty acid and optionally a fourth fatty acid, with the method comprising: a first step of chromatographic separation in liquid phase, using the initial mixture, carried out in a first unit for chromatographic separation, making it possible to recover on the one hand a first flow enriched with a first fatty acid and on the other hand a flow enriched with a second fatty acid, optionally, a second step of chromatographic separation in liquid phase, using the first flow enriched with a first fatty acid, carried out in a second chromatographic separation unit, making it possible to recover on the one hand a second flow enriched with a first fatty acid and on the other hand a flow enriched with a third fatty acid; optionally, a third step of chromatographic separation in liquid phase, using the third flow enriched with a first fatty acid, carried out in a third chromatographic separation unit, making it possible to recover on the one hand a third flow enriched with a first fatty acid and on the other hand a flow enriched with a fourth fatty acid; at least one among the first unit for chromatographic separation, the second unit for chromatographic separation and the third unit for chromatographic separation being a static bed chromatographic separation unit with a single column with recycling in stationary state.

The invention claimed is: 
     
       1. Method for purifying a first fatty acid using an initial mixture further comprising at least one second fatty acid, optionally a third fatty acid and optionally a fourth fatty acid, with the method comprising:
 a first step of chromatographic separation in liquid phase, using the initial mixture, carried out in a first unit for chromatographic separation, making it possible to recover on the one hand a first flow enriched with a first fatty acid and on the other hand a flow enriched with a second fatty acid, 
 optionally, a second step of chromatographic separation in liquid phase, using the first flow enriched with a first fatty acid, carried out in a second chromatographic separation unit, making it possible to recover on the one hand a second flow enriched with a first fatty acid and on the other hand a flow enriched with a third fatty acid; 
 optionally, a third step of chromatographic separation in liquid phase, using the third flow enriched with a first fatty acid, carried out in a third chromatographic separation unit, making it possible to recover on the one hand a third flow enriched with a first fatty acid and on the other hand a flow enriched with a fourth fatty acid; 
 at least one among the first unit for chromatographic separation, the second unit for chromatographic separation and the third unit for chromatographic separation being a static bed chromatographic separation unit with a single column with recycling in stationary state. 
 
     
     
       2. Method according to  claim 1 , wherein the first unit for chromatographic separation is a static bed chromatographic separation unit with a single column with recycling in stationary state; and/or the second unit for chromatographic separation is a static bed chromatographic separation unit with a single column with recycling in stationary state; and/or the third unit for chromatographic separation is a static bed chromatographic separation unit with a single column with recycling in stationary state. 
     
     
       3. Method according to  claim 1 , wherein at least two units among the first unit for chromatographic separation, the second unit for chromatographic separation and the third unit for chromatographic separation are static bed chromatographic separation units with a single column with recycling in stationary state. 
     
     
       4. Method according to  claim 1 , wherein at least one among the first unit for chromatographic separation, the second unit for chromatographic separation and the third unit for chromatographic separation, is a chromatographic separation unit with several columns. 
     
     
       5. Method according to  claim 1 , wherein:
 the first step of chromatographic separation is implemented with a first eluent which is a hydro-organic eluent; and/or 
 where applicable, the second step of chromatographic separation is implemented with a second eluent which is a hydro-organic eluent; and/or 
 where applicable, the third step of chromatographic separation unit is implemented with a third eluent which is a hydro-organic eluent. 
 
     
     
       6. Method according to  claim 5 , wherein:
 the first eluent is a ketone/water mixture; 
 where applicable, the second eluent is an alcohol/water mixture; 
 where applicable, the third eluent is a ketone/water mixture; 
 where applicable, the first eluent is different from the second eluent and where applicable, the third eluent is different from the first eluent and from the second eluent. 
 
     
     
       7. Method according to  claim 1 , wherein:
 the mass concentration of the first eluent in organic solvent(s) is controlled to the nearest 2%. 
 
     
     
       8. Method according to  claim 1 , wherein the first fatty acid is a first polyunsaturated fatty acid. 
     
     
       9. Method according to  claim 1 , comprising:
 at least one step of chromatographic separation between the first fatty acid and a compound or compounds that are more retained than the latter; and/or 
 at least one step of chromatographic separation between the first fatty acid and a compound or compounds that are less retained than the latter. 
 
     
     
       10. Method according to  claim 1 , wherein at least one among the first unit for chromatographic separation, the second unit for chromatographic separation and the third chromatographic separation comprises a separation column that has a length greater than or equal to 5 cm; and/or that has a diameter greater than or equal to 10 cm. 
     
     
       11. Method according to  claim 1 , wherein:
 the initial mixture which supplies the first unit for chromatographic separation comprises less than 80% of organic solvents; and/or 
 where applicable, the first flow enriched with a first fatty acid which supplies the second unit for chromatographic separation comprises less than 80% of organic solvents; and/or 
 where applicable, the second flow enriched with a first fatty acid which supplies the third unit for chromatographic separation comprises less than 80% of organic solvents. 
 
     
     
       12. Installation for purifying a first fatty acid using an initial mixture, with the installation comprising:
 a first unit for chromatographic separation in liquid phase, supplied by a supply duct of initial mixture, and to which are connected at the outlet on the one hand a first duct of flow enriched with a first fatty acid and on the other hand a duct of flow enriched with a second fatty acid; 
 optionally, a second chromatographic separation unit in liquid phase, supplied by the first duct of flow enriched with a first fatty acid, and to which are connected at the outlet on the one hand a second duct of flow enriched with a first fatty acid and on the other hand a duct of flow enriched with a third fatty acid; 
 optionally, a third chromatographic separation unit in liquid phase, supplied by the second duct of flow enriched with a first fatty acid, and to which are connected at the outlet on the one hand a third duct of flow enriched with a first fatty acid and on the other hand a duct of flow enriched with a fourth fatty acid; 
 wherein at least one among the first unit for chromatographic separation, the second unit for chromatographic separation and the third unit for chromatographic separation is a static bed chromatographic separation unit with a single column with recycling in stationary state. 
 
     
     
       13. Installation according to  claim 12 , wherein the first unit for chromatographic separation is a static bed chromatographic separation unit with a single column with recycling in stationary state; and/or the second unit for chromatographic separation is a static bed chromatographic separation unit with a single column with recycling in stationary state; and/or the third unit for chromatographic separation is a static bed chromatographic separation unit with a single column with recycling in stationary state. 
     
     
       14. Installation according to  claim 12 , wherein at least one among the first unit for chromatographic separation, the second unit for chromatographic separation and the third unit for chromatographic separation is a chromatographic separation unit with several columns. 
     
     
       15. Installation according to  claim 12 , wherein at least one among the first unit for chromatographic separation, the second unit for chromatographic separation and the third chromatographic separation unit comprises a separation column that has a length greater than or equal to 5 cm; and/or that has a diameter greater than or equal to 10 cm. 
     
     
       16. Method according to  claim 4 , wherein at least one among the first unit for chromatographic separation, the second unit for chromatographic separation and the third unit for chromatographic separation is a simulated moving bed or actual moving bed system or a system in which the injection points and the collection points of the flows are displaced periodically in an asynchronous manner. 
     
     
       17. Method according to  claim 8 , wherein:
 the first polyunsaturated fatty acid is eicosapentaenoic acid; or 
 the first polyunsaturated fatty acid is docosahexaenoic acid; or 
 first polyunsaturated fatty acid is arachidonic acid; or 
 the first polyunsaturated fatty acid is docosapentaenoic acid. 
 
     
     
       18. Method according to  claim 9 , comprising:
 the first step of chromatographic separation which is a step of chromatographic separation between the first fatty acid and a compound or compounds that are more retained than the latter, then the second step of chromatographic separation which is a step of chromatographic separation between the first fatty acid and a compound or compounds that are more retained than the latter, then the third step of chromatographic separation which is a step of chromatographic separation between the first fatty acid and a compound or compounds that are less retained than the latter. 
 
     
     
       19. Installation according to  claim 13 , wherein at least two units from among the first unit for chromatographic separation, the second unit for chromatographic separation and the third unit for chromatographic separation are static bed chromatographic separation units with a single column with recycling in stationary state. 
     
     
       20. Installation according to  claim 14 , wherein at least one among the first unit for chromatographic separation, the second unit for chromatographic separation and the third unit for chromatographic separation is a simulated moving bed or actual moving bed system or a system in which the injection points and the collection points of the flows are displaced periodically in an asynchronous manner.